SOUTH BEND, Ind. -- As Brian Kelly was finishing up his postgame press conference Saturday, an unexpected visitor made an appearance during the penultimate question.

"Jaylon, we'll be done in a second," Kelly said to Jaylon Smith, who had entered prematurely. "I know it's your press conference, but I'll be done in a second, and we'll let you get going. Is that all right?"

"Sorry," Smith said to the room of reporters. "I'm new to everything."

Within 24 hours, it turned out the freshman linebacker would be a seasoned veteran by Notre Dame's defense's standards. The Irish are hurting on that side of the ball -- just trying to get by, in a sense, with this weekend's game at Pitt preceding a much-needed bye before a two-game stretch against BYU and at Stanford.

Safety Eliar Hardy (left) is one of several Notre Dame reserves that were pressed into action due to injuries. Jonathan Daniel/Getty Images

BCS dreams have essentially taken a backseat to figuring out just who is going to play and where, and how the remaining available guy will get ready for when their time comes.

"I think this is probably close to the pinnacle," Kelly said during Sunday's teleconference when asked if this defense has been hit as hard as any he's had in 23 years as a head coach. He added: "They don't give you any points for complaining about it. If they did, I'd complain every minute. So we just take care of it internally and get the next guy ready."

It only gets worse up front, where Kona Schwenke is lost for at least this Saturday's game at Pitt because of a high-ankle sprain suffered on the Midshipmen's final drive. And Schwenke was only starting these last two games in place of nose guard Louis Nix III, who at first was ruled to have a shoulder injury suffered in the USC game, and then knee tendinitis, and now tendinitis and a small meniscus tear, though the school says he will practice this week after undergoing an MRI Sunday. Before that, Schwenke filled in for end Sheldon Day, who missed most of a three-game stretch after leaving a Sept. 14 game against Purdue with a high ankle sprain, and then re-aggravated said ankle sprain against Navy.

And no, it is not a coincidence that most of these injuries have come during this two-game stretch against Air Force and Navy, teams that often cut-block.

"It's unfortunate," Kelly said. "It's the style of offense that the academies play. It is what it is."

Kelly said it will make sense to possibly avoid scheduling multiple option teams in a single season, but that is a bridge he will cross when he gets to it. For now, his next-man-in philosophy is being tested by, well, a lack of next-men-in.

He said he guards against that by putting those who saw 15 or fewer plays in a game through extra conditioning that following Monday, while reserves get roughly half the work of the starters during 11-on-11 and scout team work in a given week.

"I think that we're so close that you don't really think about it in terms of, Oh, I've never seen you out here," redshirt senior linebacker Dan Fox said. "We get a lot of guys in at practice, there's a lot of reps to go around, so next man in and next man in."

The last of those names, Hardy, helped set Smith up for the game-clinching tackle on Navy's Shawn Lynch during the visitors' final fourth-and-4 try. And he was only there because Austin Collinsworth suffered a neck strain that will require an MRI Monday.

Fellow safety Elijah Shumate, meanwhile, is expected to play against the Panthers after being sidelined the last three games with a hamstring injury, though Kelly had said the sophomore would play going into the Navy game, too.

There are also the knee injuries to left guard Chris Watt (PCL) and cat linebacker Ishaq Williams (ACL), both of whom left the Air Force game a week ago but only one of whom, Watt, could possibly return this week, depending on how quickly the redshirt senior can acclimate to the knee, which will not require surgery. Williams was in an immobilizer this week and could possibly return for the Nov. 23 BYU game.

The return of Watt would give Notre Dame four of its five starters back on the offensive line, as it lost right guard Christian Lombard for the season because of back surgery after the USC game. Still, the bruises have taken their biggest tolls on the other line, which during the spring and summer lost reserves Chase Hounshell (shoulder) and Tony Springmann (knee) for the season, in addition to seeing freshman signee Eddie Vanderdoes leave for UCLA.

All of it leaves the Irish, winners of four in a row, crawling to the finish line, every last piece of Kelly's three straight top-10 recruiting classes fitting into the plan for his push toward a second straight BCS-bowl berth.

"We are running out of next men. We're at that point where from a defensive standpoint, and particularly the defensive line, we're left with very few options," Kelly said, adding, "We'll figure something out. We'll get 11 guys out there. It's just not going to be one of those things where we're going to have the same group of guys out there all the time. As you know, we're going to have to find a way to stop a big, physical offensive line at Pittsburgh, and that is the thing that concerns you the most."